Some consumers are hesitant to change their cell phone provider, even if they see a better deal, simply because too many people already know their existing cell phone number. Meanwhile, that cell phone contract service may be costing you an arm and a leg every month. You can better manage your cellular budget with prepaid, and you don't have to lose your old cell number. Depending on your carrier, there may be a small fee involved for the transfer of service.
The FCC has required most carriers to implement Local Number Portability (LNP), which is a service that lets you transfer a phone number to another carrier, so long as the new carrier is still in your local area. You can take advantage of the LNP mandate to switch wireless carriers and keep the same number, or even to transfer your landline phone to a cell phone. You can't transfer a pager number, toll free number, or some other types of special use numbers.
Usually, when you transfer your phone number from an old service to a new service, your old service will be disconnected automatically. If your old service was a contract type cell phone service, and your contract has not yet expired, you may still have to pay fees to the old service. But if you're transferring between prepaid services, as always, no long-term contracts or related fees will apply.